Geothermal heat pump based heating and cooling systems (Geothermal Systems) have been in use for over 30 years, but have recently realized dramatic increases in popularity. In general, a Geothermal System is comprised of three main parts: a ground heat exchanger (GHX), a heat pump or system of heat pumps, and a system of air handling and distribution devices. The heat pumps and air handling or distribution devices are located inside a building to be conditioned, while the GHX is located, as one would expect, outside of the building. Generally, the GHX itself comprises long lengths of polyethylene piping buried in the ground, and the distribution piping connecting the GHX to the heat pumps.
In operation during heating months, closed loop Geothermal Systems enable absorption and transfer of heat from the ground to the heat pump(s) via a heat transfer fluid (Fluid). The heat pumps extract heat from the Fluid for delivery to the building, reducing the Fluid's temperature by several degrees. The Fluid is then transferred back to the ground to repeat the process. In cooling, the process is essentially reversed as the heat pump extracts heat and humidity from the air inside the building, injects it into the Fluid, increasing the Fluid's temperature by several degrees, and then transfers the heat back to the ground by pumping the Fluid through the GHX. After the heat is rejected to the ground, and the Fluid temperature reduced, the Fluid is then circulated back to the building's heat pumps to repeat the process.
To enable the heat absorption and rejection from the ground miles of piping may need to be buried in order to transfer enough heat to or from the building. The greater the size of the building, the more pipe must be installed in the ground for the system to be effective. This network of buried piping is referred to as a ground heat exchanger or GHX. To minimize the energy required to circulate the Fluid within the closed loop the piping is often installed in parallel configurations. I.e., the total Fluid flow required to properly operate the Geothermal System is typically divided among many circuits of buried closed-loop piping as opposed to a single continuous loop. These parallel circuits are often coupled together at a manifold in or near the building. The heat transfer characteristics of the system are dependent on achieving a desired Fluid flow rate, thermal capacity, and fluid pressure within all circuits of the GHX and the associated distribution piping.
The reliability and dependability of the Geothermal System, and its ability to provide desired comfort for the building's inhabitants, is highly sensitive to unrestricted Fluid flow, accessibility of all of the piping circulation circuits of the GHX, and the consistency of overall system pressure. It is therefore desirable that proper preparation of the GHX be performed to control these elements.
If a GHX is not properly prepared for service, the following undesirable conditions are probable:                Air introduced into the closed system during installation will likely remain entrapped. This condition can cause portions of the GHX to simply “lock out,” forcing the Fluid to circulate along an easier path within the parallel circuitry. This reduces accessibility of desirable heat absorption and rejection capacity, perhaps for the life of the system.        Debris, such as earthen materials, plastic pieces, etc., introduced into the system during installation can be entrained in the Fluid, travelling to straining devices inside the building which serve to protect heat pumps and other sensitive equipment. This debris accumulates, gradually restricting Fluid flow and reducing heat pump capacity to the point of possible failure. This condition is highly undesirable as the removal of the accumulated debris is difficult, requiring the isolation of Fluid flow to the affected device, disassembly of the piping, and likely introduction of undesirable air to the closed system.        GHX leaks, and associated loss in pressure within the closed system of piping, can cause a multitude of problems including, circulating pump cavitation, contamination of the Fluid, and release of Fluid to the environment and, if left untreated, total System failure.        
Accordingly, the performance of the entire Geothermal System relies on the physical integrity of the piping comprising the ground heat exchanger and related distribution piping. Furthermore, the removal of entrapped air and entrained debris from the closed loop system of piping, to the extent possible, are related to the physical integrity and energy efficiency of the system.
Current systems for testing typically utilize a gas/diesel powered pumps and simple manual valving and visual observations of pressure meters to provide flushing and pressurization for testing. Such systems lack records for verification, lack automation for precise control of the systems, lack controls to prevent pressure surges and damage to equipment and piping.